Commercial Layers and Layer Breeders

Coccidiosis

Intestinal coccidiosis was diagnosed in 30-day-old layer pullets that had been looking unwell. Post mortem examination revealed slight dilation of the mid to lower intestine from Meckel's diverticulum to ileocaecal junction with focal impaction of contents and necrosis of intestinal mucosa. Wet smear examinations revealed large numbers of coccidial oocysts. The location and appearance of these lesions strongly supported a diagnosis of E. brunetti infection.

Fowl cholera

Fowl cholera was found to be the cause of a protracted mortality in a flock of 52-week-old free-range layer hens. Pasteurella multocida was recovered in pure cultures from peritoneal swabs.

Broilers and Broiler Breeders

Infectious bronchitis

Bury received a number of submissions for PCR testing for infectious bronchitis virus. Of these, one submission of oropharyngeal swabs from 29- day-old broilers identified an IB virus with 98.6 per cent similarity of the S1 sequence to the European QX strain. A second submission from 24-day-old broilers identified an IB virus with an S1 similarity percentage of 99.3 to the D274 strain of IB virus.

Enterococcus cecorum

Twenty, one-day-old broilers were submitted from sheds of 53,000 birds where there had been an increase in leg culls, ill thrift and some mortality. E. coli and staphylococcal infections had been problems in the previous flock. Pericarditis associated with Enterococcus cecorum infection was the predominant finding at post-mortem and one bird had a staphylococcal hock joint infection.

In another case, the infection was responsible for increased mortality occurring in four sheds of 28,000 three-day-old broiler breeder chicks. Marked fibrinous pericarditis and enlarged spleens were seen in four of five birds examined and this was found to be associated with enterococcal infection.

Staphylococcus aureus

Staphylococcus aureus infection was found to be responsible for the deaths of 50 to 60, 10-week-old broiler chickens. The group of 200 birds had been placed at one day of age. Of the seven birds examined at Carmarthen, six were diagnosed with S. aureus septicaemia with the organism being isolated in pure growth from almost all sites from which bacteriology was carried out, including subcutaneous fluid in one of the birds with dermatitis.

Coccidiosis

Chronic caecal coccidiosis due to Eimeria tenella was seen in 30-day-old broilers with a history of poor body gain, poor water consumption and deterioration of the litter condition. Post mortem examination revealed slightly dilated caeca containing compact faecal material with caseous tags, but no fresh blood. Wet smear examination of caecal contents revealed large numbers of oocysts consistent in size and location with those of E. tenella.

Backyard Flocks

Salmonella pullorum

Three live and two dead seven-day-old chicks were submitted from a small backyard exotic poultry breeder for post-mortem examination to investigate an increase in chick mortality post-hatching and infertility in adult hens. Clinical signs included a tendency to huddle, inappetence, weight loss and wet vents, although sudden deaths had also occurred. Necropsy revealed orange coloured livers and typhlitis with the presence of caecal cores. Salmonella pullorum was isolated from the liver of the chicks.

Turkeys

Fowl cholera

Twenty out of a group of 100 turkeys had died over a few days. Ten of the 18-week-old turkeys had been found dead on the day of submission. At postmortem, there was bloody mucus in the pharynx and oesophagus, enlarged spleen, fibrin over the liver and loops of intestine, fibrinous exudate within the pericardium, dark lungs and fibrinous material over the lungs. Pasteurellosis was diagnosed following isolation of Pasteurella multocida from lung, heart and liver samples.

Ornithobacterium rhinotracheale

Ornithobacterium rhinotracheale was diagnosed as the cause of an outbreak of pneumonia and air sacculitis in turkey poults. There were 400 16-week-old stags and 2,100 12-week-old hens kept in separate pens in the same building and able to free range. Respiratory disease had been treated with amoxicillin about a month earlier, which had resulted in an improvement, but there was still some sneezing. At the end of October, six turkeys had died in the last two days and a lot of poults were reportedly sneezing despite a further recent treatment with tetracycline. Serology indicted the potential involvement of Mycoplasma meleagridis.

Erysipelas

A flock of 500, three- to four-month-old turkeys nearing slaughter weight experienced a sudden and dramatic outbreak of disease with sudden deaths, recumbency and dyspnoea. Half of the birds died. Following negation of notifiable disease, tissues were submitted for culture resulting in the recovery of Erysipelothrix rhusiopathiae from a spleen sample indicating erysipelas as the cause of the disease outbreak.

Gamebirds

A group of pheasants was received with a history of swollen eyes, gasping respirations and rising mortality in released birds. Post mortem examination confirmed varying degrees of sinusitis ranging from mucoid to severely caseous sinus contents, and in some birds there was a severe airsacculitis accompanied by granuloma-like lesions in the lungs. A variety of infectious agents was detected in the birds including Mycoplasma synoviae (rarely confirmed in gamebirds), a coronavirus similar to infectious bronchitis virus, Pasteurella multocida and Ornithobacterium rhinotracheale (ORT).

Further Reading

-

You can view the full report by clicking here.

Further Reading

-

Find out more information on the diseases mentioned in this article by clicking here.